<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        body {
            /* background-color: #000; */
            display: flex;
            justify-content: center;
            margin-top: 30px;
        }

        .box {
            width: 1226px;
            height: 460px;
            background-color: cadetblue;
            background-image: url(./xiaomi15.jpg);
            background-size: cover;
        }

        .list {
            width: 234px;
            height: 420px;
            background: rgba(105, 101, 101, .6);
            padding: 20px 0px;
            position: relative;
        }

        .list ul {
            list-style: none;
        }

        .list ul li {
            width: 100%;
            height: 42px;
            line-height: 42px;
            text-align: left;
            padding-left: 30px;
            box-sizing: border-box;
        }

        .list ul li:hover {
            background-color: #ff6700;
        }

        .list ul li a {
            display: inline-block;
            text-decoration: none;
            color: #fff;
        }

        .door {
            height: 460px;
            background-color: #fff;
            position: absolute;
            top: 0;
            left: 234px;
            box-shadow: inset 0 0 10px rgba(0, 0, 0, .5);
            opacity: 0;
        }

        .door1 {
            width: 234px;
            height: 50px;
            background-color: rgb(187, 114, 25);
            margin: 10px 10px;
            line-height: 50px;
            text-align: center;
            display: inline-block;
        }

        .list ul li:hover > .door {
            opacity: 1;
        }
    </style>
</head>

<body>
    <div class="box">
        <div class="list">
            <ul>
                <li>
                    <a href="#">手机</a>
                    <div class="door">
                        <div class="door1">手机</div>
                    </div>
                </li>
                <li>
                    <a href="#">电视</a>
                    <div class="door">
                        <div class="door1"></div>
                        <div class="door1"></div>
                    </div>
                </li>
                <li>
                    <a href="#">家电</a>
                    <div class="door">
                        <div class="door1"></div>
                        <div class="door1"></div>
                        <div class="door1"></div>
                        <div class="door1"></div>
                        <div class="door1"></div>
                    </div>
                </li>
            </ul>
        </div>
        <div class="banner">

        </div>
    </div>
</body>

</html>